Alabaster or onyx gemstone carved necklace

Not sure what the stone is, I think it's either alabaster or onyx could be wrong. Definitely a natural gemstone since it's very cold to the touch this necklace is a vintage item from my great grandmother's house. we're trying to get rid of some of her old costume jewelry. This necklace is 22 inches. if your interested in more vintage jewelry we have other mystery box listing worth checking out and we will be posting more items soon.